1. Technical Field
The invention relates generally to semiconductor interconnects, and more specifically, to chip-to-chip integration and off-chip connection schemes for semiconductor devices.
2. Background Art
A typical electronic system may comprise a variety of electronic components, fabricated on a variety of material. Very often, it is impossible for these various components to be integrated on a single substrate due to performance considerations or cost concerns. Consequently, these electronic components are packaged and externally electrically interconnected to function as a unit.
In the past, semiconductor packages have been electrically interconnected through wire bonding and/or the use of a C4 flip chip. Unfortunately, as packages become more dense and total performance gain becomes more important for high power chips in the system, the use of wire bonding and flip chips to form off-chip connections is not practical in many applications. Specifically, a significant performance degradation is caused by a wire bond induced parasitic inductance from a chip to a printed circuit board. Although a flip chip overcomes the parasitic inductance problem, the thermal properties of the flip chip severely limit the ability to cool high power chips, and adding an external heat sink to provide thermal conduction causes packaging constraint and increased chip operation ambient temperature.
There are inventions in the past with electronic components stacked together, whereby electrical communication between components are made possible via feed-throughs in the semiconductor bodies. Examples are found in the following U.S. Patents: U.S. Pat. No. 5,128,831, issued to Fox, III et al. in July 1992; U.S. Pat. No. 5,481,133, issued to Hsu in January 1996; U.S. Pat. No. 5,424,245, issued to Gurtler et al. in June 1995; U.S. Pat. No. 5,202,754, issued to Bertin et al. in April 1993; and U.S. Pat. No. 5,270,261, issued to Bertin et al. in December 1993. Although feed-throughs are used in the stacks, the assembled stacks are then attached onto a printed circuit board with the off-chip wiring schemes, long routing traces and all the associated prior art shortfalls. Furthermore, the aforementioned patents do not provide proper heat dissipation for high power chips, and low inductance connections to different levels of packaging, such as a circuit board.
It is thus an advantage of the present invention to provide through-chip conductors and chip-to-chip and off-chip connections for a semiconductor device and the method for making the same that eliminates the above described defects.
The advantages of the invention are realized by a semiconductor device having active devices on the front surface, a first through-chip conductor having first electrical/physical characteristics passing from the front surface of the device to the back surface, a second through-chip conductor having second electrical/physical characteristics passing to the back surface, and an off-chip or chip-to-chip connector electrically connecting the active devices on the front surface to a different level of packaging.
The foregoing and other advantages and features of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings.